Digester



100. 00MP0s|T|0NS, Cross HGTerence Examm 76C0AT|NG O-R PLASTIC. Y;

Pateted 000.00, 1804.

Y ATTORNEY l. To all wtvonftvv it may concern.- 4

Beit known that `I, HENRY W. STEBBINS,

UNITED STATES 5,28, ma l PATENT OFFICE..

J. H. FRIEND, F DAYTON, omo.

' ullcss'TsR.'

srsomcarrou forming parte: Leamratenmo. s2s,4oo,a.ieacaobr"ao,'1so4. Application led January 26,1894. No. 4:98'156.l (No model.)

of West Carrollton, county of Montgomery,

State of Ohio, have invented a new and useiul- Improvement in Digesters;and I do declare "the following tobe a full, clear, and exact der scription of the invention, such as-will .en-y

able others skilled 'in the art to which it ap-.II pertains` to make and use the same, reference being. had to theaccompanyingdrawings, and

`to the letters of reference marked thereon, `which form a part of this specification. This invention 4relates to digesters or boilers in which the preliminary treatment of raw material, such as wood, or other brons substance takes' place and whereby a reduction of said material to the condition of cellulose for paper-making and other purposes is effected, by the use of acids, steam heat, and pressure. The' acid most commonly used in the treatment of said material,'is sulphur-cus' acid, and iscombined with a base, usually lime, and thereby forms abi-sulphite of lime solution. AOwing tothe volatile nature of the acids .used within the digester,and their corrosive and otherwise destructive action upon the various metals that possess sufficient tensile strength to `withstand the resulting press- -ure that is generated .the steam used in the digester, it is essential that the inside of a the ,metallic shell be protected. To these j yends various means have been employed foi-' y, protecting the interior surface of the metallic shell, forming the digester, from said inj urious effects. Principally among these, is the y' use of `an acid-resisting metal, anchas lead,

variouslyapplied to the interior surface. of

.the hard metallic, shell, each having for its object a method by which to overcome the diicul-ties met in associating metals having A different ratios of expansion and contraction.

- The object of the present in venton is to providey means for securing the lead sheathi ing or lining to the hard metallic shell, and to this extent isan improvement onthe digester shown and described in Letters Patent i.; No. 405,279, granted to myself .lune 18, 1889. )In addition to the diiculties resulting from the association i .ing natpres, it

jmetals havingsnch varydund in practice that when l A.lead-is subjected to the requisite pressure,

and high and varying degrees of temperature,

the quality' of expansion, even to a degree bility increased. These ends arev accomplished, first, by the use of a lining placed next to the inner surface of the lead lining, composed of a combination of-materials, pref-V erably of a porous nature, and when formed into a composition, basa low heat conductive power and transmits only a minimum quanlining, 'next to that` adjacent to the lead, comand 'of suicient density to absorb and retain ,any change of temperature occurring within shell and lining; Fig. '2, an enlargedsection of showing one of the pockets with the lead ,remved."

jIn the following description similar 'letters of, reference will be' us`ed to indicate eorre-A spondingparts.- 1

necessary to meet that of the harder metal,

. vHENRY W. STEBBIS, 'OFWEST CARROLLTON, .ASSIGNORY 4OF ONE-HAL T0 ture, to the end that the eiciency of the di# I' gestor will be greatly enhanced, and its dura- 'tity of heat, and, secondly, by the use of a posed-of material of anon-porous nature,

an amount ot heat s ucient to counteract]l the digester, when inl operation, and fthat one of the joints; Fig. 3,'a similarsectionv A indicates nie-annular' sections, that when united, form the outer hard metal shell of the digester, withits ends terminating in conoidal shape, These sectionsarepreferably of iron "t 1- prsfei for uns nel Y" '528,400

or steel, and are placed one en thether with theedges over-lapping and tmade secur'eby means of rivets (c) the headset whichcan be headed on the inner-surface, butare preferably satedin vcounter-sunk holes in the inner-lapping contact'portions of said sections.

` When thesections Aare so united there is a series of interior annular ledges-'or shoulders (b), formed by the upper or inner edge ofeach i 1o section. g

lc-is'aseries'nf sectional annular bands, constructed of hardmetal, and abuttingwith the annular shouldered?) upon whichsaid bands A. have a normal bearing. These bandsare sex 5 cured tothe-loweror over-lappingportion of "d',-a s eriesof bolted also through the' annular bauds and steel shellndihave-for their .ffunction the securing of the leadlining B,

throughwhichsaid bolts also pass. 'Bothseries of bolts dfand d' are made to tit counter-sunk holes in the inner surface of the bands (c), so that said 4bolt.' heads lie .flush with the inner surface of said bands,iand 4 thereis presented, on the interi-or surface ofthe shell, a regular and uniformsurface. Itwill be's'een from Fig.- 3 that a portion of theband (c) has a less thjcknesstban Vthe remaining portion, which hasathick'uess equal to ef 'the' shell'r. The object of constructing these bands of un equal thickness, is to form Aa series of.- annular recesses 'or Ipockets `(e) between said bands' and thejshell, andgther'ebyproyide ecient means forsecuring the lead lining, without as wardly'bentannular` -olsets at ltheir upperedges as'isdescribed in `the'patent hereinbe fore referred to.-` Y Biderotes the lead lining, constructed of endless bands in sections, andof 'any desiredthickness, and aflength sufficient to' extend around the'interiorsurface of the shellffhese' sections areplaced in'position inthe following manner. AAu edge'of .each section is placed in its respectiveannular-'pocket ,(e) and i's--prnvided with holes through ,whichthe b ltfd) may pass. The other edge of' said. section reaches tothe top'of the next adjacent pocket which has likewisebeen filled with .another section of l`ead," and thetwo' section'sat that point are fused or nelted togetherby the use of an o xyhydrogen blow pipe', This operation is repeated 'u ntil Atheen tirefinte'rior ot the di gestor is .lined witli one continuous lining of lead. The lead so placedis prevented from leaving thepookets' bythe bolts' (d) if through any 'cause'such would be the tendency. As a fnrtherprotecton to the outer hard metal shell, and a means for preserving the 6o lead lining in a serviceable condition, I place next. thereto, two centinuousflinings (f.) ,and (g) each having lowheat-couducting qualities, and may be composed of any suitable mixf ture of substances possessing these qualities.'

composite lining (f) a mix- Pctlandnement asbesto Yture-composed or the 'shellsections Ajby Vscrew-threaded bolts constructing the shell s'cctions A,- v vit.h the insis'tingbylheaddition of non-'corrosive subul hate of ba- 'do al'. 'IE'elm'f 7o stances such as l L la de from -brcltrumfelitirarve an t 1 oc s n1 Inc, g consists o cla free from mavnesia lime or other ingrel dlens that woulifbe aecied bythe acids.

These blocks are hydraulic pressed, hard burned, and porous when completed,'and 7 5 when applied aresetin cement. .Besides having the desired heat features theyare an eiicient means of' adding strength to the coinpositelining (f). Y

' VAdjacent'. to thelinings (f) and (g),I place 8o a'further composition lling (h) composed preferablyof a mixture of I and cru l d tone or san iu'lpal e 1 composi 1 n t e a ition 85 -of non-corrosive substance such aslan'p-bl-ag slp'hate of- Emmi-and lithar e an nex o 1sv p ace an inner lining i3 i, composed of blocks, brick or tile, mad'e from fire clay or othesuiftable material and combined with 9o the filling (h) has the power of absorbing and retaining maximum quantities of heat. These act in connect-'on with the linings (f) and (g) and together effectively counteract the variations of temperature that take place ,in the d igester when it is 'in operation, and that wouid'otherwise be imparted to the lead lining and outershelh 1- Having fully described my invention, what I desire to claim and secure by Letters Patent is 1. In a digester, the'sect-iens A, of hard metal, arranged to over-lap each other and form a continuous shell or boiler, the annular shoulders (b) formed bythe inner-lying edges of each section, a series of bands having two .degrees of thickness, abutting with said shoulders and made rigid to the over-lapping edges o f the sections', whereby a series of a'nnular recesses or pockets is formed in the. in-

terior 'of the shell, in combination with alining of pliable metal arranged to extend in and over said pockets, whereby. a continuous lining'thereo is formed and maintained in posi, tionby'said pockets, and by the bolts (d) passing'therethrough, substantially as described.

2.' The combination as herein described, of

,a digestershell and internally arranged bands forming 'annular pockets therein, a lining of lead adjacent to said shell and maintained by said pockets and bolts passing.therethrough,. a heat-absorbing and acid-resisting lining composed of Portland cement, asbestos, lamp black, sulphate of barium, litharge 'and silicate of soda in suitable proportions, by means of which `a minimum and uniform degreeof pressure land temperature is maintained, and the soft metal lining and the hard metal shell thereby preserved, substantially-as herein described 3. The combination substantially as set.

'fo'rth, of adigester shell, bands forming annu lar pockets on the interior thereof, and the inroc terior of said shell preating a uniform and regular surface, a. lining of soft metal placed gainst said shell, the heat-absorbing and acid-resisting lining' (f herein described, adjacent to saidsoft metallining, the lining (g') 5 composed of porous blocks, to further prevent the transmission of heat and to Areinforce or strengthen the lining (f), the lining (h) havingaheat-absorbingand acid-resisting naturefaud the' and arranged su In testimony'v my hand this 2 Witnesses:

glazed tile (j 'all combined bstantially as specified. whereof I have hereunto set 7th day of December, 1893. HENRY W. S'IEBBINS'.

A. M. sm1vN,`

II. L. DUNN. 

